Fabrication And Characterization Of Photoelectric Properties Of LED Microdisplay

Micro LED display technology uses micron-scale LEDs as light-emitting pixel units,which can be combined with adaptive driving to achieve high-performance display technology.Compared with LCD and OLED,Micro LED chips are smaller in size,higher in brightness,higher in resolution and contrast ratio,have lower power consumption and have greater advantages in response speed and service life.The research on red,green and blue Micro LEDs and the development of full-color Micro LED display technology have made many progress in recent years,and there are also new developments in technologies such as mass transfer equipment.Micro LED will be applied in many fields such as AR/VR,wearable display,flexible transparent display,medical inspection,automotive pixel headlights and so on.At present,Ga N-based micro-light-emitting diodes still have the problem of external quantum efficiency decline,so how to improve the luminous efficiency has become a research problem of many scholars.In this paper,a green Micro LED microdisplay with a Distributed Bragg Reflector（DBR）with an effective display area of 0.42 inch and a pixel emission size of 14μm is designed and fabricated.The influence of the optical properties of microdisplays,the optoelectronic characteristics of Micro LED microdisplays with DBR were characterized,and the influence of DBR on its optical properties was studied.The main research contents are as follows:1.Using semiconductor process equipment,according to the Micro LED manufacturing process,through mask design,gluing,photolithography,development,coating,stripping substrate,bonding packaging,etc.a 0.42 inch,resolution of 480×270,A green DBR Micro LED microdisplay with a pixel size of 20μm.2.Using Macleod software to simulate the influence of different thicknesses of SiO₂films on transmittance,and through experimental design,SiO₂films were evaporated by PECVD,and the best film thickness was 270 nm and the highest transmittance was tested by Lambda 750 PE spectrophotometer.reached 92%.Compared to the sapphire die,the transmittance is improved by about 6%.3.The photoelectric performance of the green light Micro LED microdisplay is characterized by the photoelectric test platform.Under the control of the driving signal,it is concluded that the non-DBR Micro LED microdisplay reaches the peak brightness at 340 m A,which is about 540000 nits.The Micro LED with DBR structure has a peak brightness of about 1.98 million nits at 620 m A.When the driving voltage of the Micro LED is 3.4 V,the peak light output power can reach 105m W,and the energy efficiency is 9%.The EQE is improved by about 20%,the color coordinate shift is small,and the field of view is close to the Lambertian distribution.DBR will find important application in Micro LED microdisplay.